Terrible 2s

So my boyfriends son is 2 and will be 3 in a few months. I am a stay at home mom to him and at first he was kinda bad because his birth mom let him do whatever he wanted but he learned our rules really fast. He recently started being even worse than he was before. He tells us no and doesn’t listen AT ALL and when I go to pick him up or something he scratches at and bites my hands and fights me. He used to ask for food and drink normally by saying “eat!” And “drink!” But now when he’s thirsty or hungry he just throws a fit or sets a cup in my lap. He knows what he’s not supposed to do and he knows what he’s not supposed to touch or play with. Ever since this started he looks me dead in my eyes and does it anyway. It’s gotten so bad to the point I have no idea what to do. I’ve tried EVERYTHING! Does anyone know what causes this behavior or if he’s just a normal 2 yr old boy? Or what I can do about it? Also I just found out I’m pregnant yesterday so now I’m worried all the stress and picking him up will cause me to loose the baby. This is my first pregnancy so I don’t know much. Anything helps! Thanks in advance!